Shock-absorber



H. BURRMANN.

SHOCK ABSORBER. APPLICATION men NOV. 9. 1920 3 SHEETS-SHEET l Patented Mar. 29, 1921.

Z 51? M12. Mavis 1 H. BURRMANN. 'SHDCK ABSORBER. APPFICATION FILED NOV. 9, I920.

Patented Mar. 29, 1921.]

3 SHEETS-SHEET 2.

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1 lll lllllll illlll fiwlay fiZ/HHMANN Pm M mam ATTUHNEYS HENRY BURRMANN, OF DAVENPORT, IOWA.

SHOCK-ABSORBER.

Application filed November 9, 1920.

To all whom it may concern:

lie it lrnown that I, lrlnnnr BURRMANN, a citizen of the United States of America, and a r ident of Davenport, county of Scott, and ii'atli'fi oi? lowa, have invented certain new and useful improvements in Elhoch-Alr sorbers, of which the following is a full and clear specification.

This invention relates to that type of shock absorbers adapted for connection to the tree end ot a leacli-spring to form a suppleinental or auxiliary spring device to thereby assist the leatlispriug in cushioning; the running; oi. the vehicle, the preferred form of my device embodying also a snubber means to cushion or break the recoil, as more fully hereinafter set forth.

in the drawing- Figure l is a view partly in section and partly in side elevation oi? the preferred torn). oi my device;

Figs. 2 to 1i, inclusive, are views of dctails hereinafter described, partly designated by reference characters;

Figs. 12 and 1.8 are detail views showing a modified iforin oi the snubber;

Fig. la; a view ot details oil the swing ingpressureplates or bars which are used in both forms of my apparatus;

Figs. 15 to 20, inclusive, are views of a niodilied term of my apparatus partly illustrated. in Figs. 12 and 18;

Fig. 21 is a detail view of the twisted or screw snubber-rod.

Referring to the d 'awings by reference numerals, designates the usual leaf-spring whose free end is connected by a pair of links 521 to the lower ends of a pair 01'' pressurelevers each 01!? said levers being pro vided with an integral car 23 about midway its length, these cars being pivotally mounted on a horizontal bolt L4; carried by a bracket this bracket being adapted to be rigidly atlired to a suitable part of the vehicle, it being}; shown in Figs. 1 and 16 as being adapted to be fastened to the brakedrum of the rear axle oi a Ford type of motor vehicle, and in Figs. 15, 7, S and 9 as adapted i'or attachment to the front axle of the same type of vehicle.

Pivotally mounted on a horizontal bolt 26 carried by the upper ends of the pressurelevers 212 is a cap 27, the connection to said bolt being by means of cars 28, and the cap being provided on its face opposite said ears with an annular boss 29. Aflixed in the outer Specification of Letters Patent.

Patented Mar. 29, 1921.

Serial No. 422,907.

ends of a pair of arms 30, formed integral with the bracket 25, is another horizontal bolt 31, which is pivotally mounted on another cap 32 which is a companion to cap 27 Between these two caps is arranged a coil-spring 33 whose normal tendency is to expand, thus tending to press the caps apart. The positions of the pivot-bolts 26 and 31 are such that the spring 33 has its axis inclined upwardly and away from the leafspring; 20, to thereby favorably position the spring -for compression by the load of the vehicle, the strain of the load being transmitted through the shackle-links 21 and the pressure-levers 22 and the top cap 29, the lever 223 being inclined outwardly and upardly to thereby transmit pressure directly and centrally to the spring 33, both caps 27 and 32 and the pressure-levers 22 being pivotally mounted on horizontal axes to enable these parts to readily adjust themselves so as to at all times maintain pressure on the spring cent-rally thereof, it being obvious that this construction permits the spring to bodily shift its angular position with varyingload pressures.

To cushion and break up the recoil, I provide a snubber device. The preferred form oi? this device is shown in Fig. 1. In this form of the device I rotatively mount centrally in the cap 2'? a. rod 34, this rod being held to the cap by means of a locked nut 35 ttilllXGCl to the outer end of the rod, the rod being shouldered to abut against the inner face of the boss 29. This rod depends centrally into the spring and at its lower end it has rigidly attached to it a cap 36. This rod passes through another cap 37' which is a companion to cap 36 in that between these two caps there is conlined a eoilspring 38 whose tendency is to expand in opposition to the niain-spi'im, 33. The cap 37 is formed integral with a pair oi plates 39 whose lower ends are 'ast integral with the lower main cap 32, thereby constitutingsaid cap 37 rigid abutment for spring 38, which abutment will, of course, swing with the lower cap under the varying conditions of the load. The stem 34 is desirably square in cross-section and is twisted to virtually convert it into a screw. This spiral portion of the rod passes through a hole in the center of the cap 37, this hole being square in cross-section but having its four inner walls slightly spiraled'to conform to the four spiral faces of the rod.

7 when the main spring expands upon release of the load pressurethe snubber-spring will be again compressed and the rod Ell will be given a reverse rotation. This recompression of the snubber-spring 3S and the triction caused by the quick rotation of the rod 3% will gently and smoothly overcome the destructive eiieets of the rebound.

In Figs. 1. l0 and 11. it will be seen that the bracket is provided with a main depending plate having a bolt-hole for bolting it to the brake-drum, wnile in Figs. T and 8 this bracket is termed two depending hooks -11 adapted to engage under the .tlanges of the axle, these depending hooks being detaehably held to the axle by means of a goose-neck bolt 42 rigidly a iixed to the axleand having its upper end provided with a horizontal tubular eye which its between the hooks 4&1 and is secured thereto by a bolt 4%.

The snubber device illustrated in Figs. 12, 13 and 15 to 20, inclusive, performs substantially the same function as that which has been heretofore deseribet. consists of a pair of long fiat bars hinged together at their lower ends on bolt 31 and extending entirely through th main coil-spring and emerging at the top thereof, the top-cap 2T icing provided with a square hole to permit the upper ends or" these members 15 to thus extend beyond the spring. These fiat members are pressed apart at their upper ends by coil-spring 4-6 mounted upon a pin 47 extending through holes in the upper ends of said bars 45. The outer faces of the bars 45 are serrated at- 48, these serrations being preferably wave-like or rounded in formation, and at a point above the series of corrugations these members are provided with downwardly-facing shoulders 49 which normally (that is. when the vehicle is without appreciable load) rest upon rollers 50 journaled between ears formed on the upper face of cap 27.

It will be observed that with this term of snubber the spring 4 6 acts in the same manner as spring 38 in the other form. The corrugations 48 together with the rollers 50 serve to destroy unpleasant noises as well as to reduce the wear of the parts and also increase smoothness of operation.

The nature and scope oi the invention having been thus indicated and its preferred embodiment. having been specifically dcscribed, what is claimed as new is:

l. in combination with a leaf-spring, a bracket having a pair of laterallypro iccling arms, a pivot-bolt carried at the outer cnds oi these 2 rnis, a pair of pressure-levers pivotally connected at their lower ends to said leafspring and midwav their ends to said bracket, the levers being an angcd outside of said armsand having guiding contact therewith, the upper ends oi said levers extending above said arms, a cap pivotally hung on the upper ends ot said levers, a companion cap pivotally mounted on the outer ends of said arms, and a compression spring arranged betwcen said caps, substantially as set forth.

"3. l" :v auxiliary spring tor vehicles, a. pair of rocking levers iivotally connected at their lower ends to the vehicle lea t-spring and inclining upwardly and away 'l'rom said lent-spring, these levers being pivotally supported at a point between their ends. a cap pivotally swung between the upper ends of said levers. a companion cap and means for pivotally supporting it at a point near to said leaf-spring. and a compression snring arranged between said caps. for the purposes set forth.

3. in auxiliary spring tor vehicles comprising 1. main coil-spring. a pair ot caps between which the spring is conlincd. means "for compressing the spring undcr load prcs sures. and a snubbcr device incloscd within the spring consisting of a rod rotativcly mount d in the upper cap and having spiral faces. a snubber cap aliixcd to the lower end oi this red, another snubbcr cap through which said rod passes. this snubbcr cap being fixedly arried by one of the cups of ibc main spring. and a snubbcr-spring ma'n tained at a normal compression bctwccn .--:iii snubber-caps.

l. in auxiliary spring for vehicles comprising a main coil-spring. a pair of caps between which the spring is coniined. mcans tor compressing the spring under load prcs sures consisting ot a rod carried by one oi the caps and having a snubber-cap ailixcd to its inner end, another snubbcr-cap ailixcd to the other main cap, and a coil-spring maintained und 1' compression in opposition to the main spring.

5. Ir bracket or support tor an auxiliary spring ot' the type set forth consisting ot a pair of arms having a pair of depending hooks adapted to engage the llange oi the axle, and a bolt bolted to the axle and having a goose-neck portion extending up between said hooks and bolted thereto.

In testimony whereof I hereunto ailix my signature.

HENRY BURRMANN.

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